To_balun_or_not_to_balun2

that is the question, for many ham radio operators. A simple, resonant, single band, plain-vanilla horizontal dipole, does really need a 1:1 balun… or not? To investigate the differences between a dipole having a 1:1 balun and another one directly connected to the coaxial cable, I build a 40m band dipole with a remotely controlled switch […]

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tyt_in_jail

It can happen that a “PC Programming Password”, set on the Tytera MD-380/Retevis RT-3 “CPS” programming software, is lost or forgotten. If that happens, there is no way to program the radio from your PC ever again. However, there is a simple workaround: install the md380tools by Travis Goodspeed KK4VCZ; follow carefully his instructions for […]

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tytera_DM380_format

This page documents the format of the Tytera DM380/Retevis RT-3 codeplug binary file. This is not an official format definition but it has been determined by changing settings with the “CPS RT3” program version V1.30.0. This specification is used by the rdt2csv conversion utility to export/import codeplugs in the CSV format. General rules The codeplug, with […]

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rdt2csv

The recent Tytera MD-380, also known as Retevis RT-3, is very nice DMR portable UHF rig. However, one of its weak points is the programming software. While DMR for utility use often requires simple programming, when used for HAM radio, the big and evolving number of available repeaters, users and zones makes programming a big […]

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LongwireEng

One of the most tempting all-band cheap antenna solution when a lot of space is available is the “long wire”. The idea is to lay a wire as long as possible and to feed it at one of its ends, while the other pole is grounded. Some kind of fixed impedance transformer plus maybe a tuner […]

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CarPhone

Questo post, purtroppo incompleto, fa seguito alle numerose richieste che ho ricevuto relativamente ad una mia sperimentazione, ormai risalente al 2011, che vedeva coinvolta la parte RTX di un vecchio telefono veicolare Italtel a 450 MHz commercializzato negli anni ’80 dalla SIP. Di questo telefono esistono due modelli, MB-44S, più vecchio ed ingombrante (a destra […]

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Men vs. machines

Davide – mi scrive Tino IK2EXH – sabato prossimo eseguiremo un’esercitazione ARI-RE che prevede la dimostrazione dell’impiego dell’APRS e della relativa connettività tramite aprs.fi per coordinare pattuglie appiedate in operazioni di ricerca a terra. Utilizzeremo il tuo digipeater in UHF perché sulla frequenza VHF, con i portatili, non si riesce a transitare. APRS L’APRS è un sistema […]

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VSWR_line_radiation_myth

In the world of HAM radio, there are several myths that survive through generations despite them clashing with laws of physics. However it is quite interesting to see how easy is to debunk some of them with very simple experiments. The radiating line myth In HAM radio discussions “experts” frequently advise against antennae tuned by a tuner […]

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ft897_chi_sono_i_fessi

[Also available in English] – Praticamente tutti i principali produttori di ricetrasmittenti, sia radioamatoriali che civili, hanno in catalogo modelli UHF 400-470 MHz dotati di serie di connettore SO-239, cioè la femmina del vetusto “PL”. In molti casi, forniscono connettori diversi in base al mercato: N in Europa, PL nel resto del mondo. Ad esempio, l’Icom […]

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